It is used in the executive branch of government, with different meanings in different political systems, and is also used in other organizational settings.
The senior administrator may be considered a second-in-command to a politically appointed cabinet minister or other government official (e.g. in the United States), or they may be considered a head or chief executive of a government department (e.g. a permanent secretary).
In France the Undersecretary of State (sous-secrétaire d'État) was a governmental role created during the Hundred Days and institutionalized in 1816.
In the Holy See, undersecretary is a title given to senior administrative officials working in the dicasteries of the Roman Curia.
In Hong Kong, undersecretary is a position created in 2008 to work closely with bureau secretaries and top civil servants to implement the Chief Executive's policy blueprint and agenda in an executive-led government.
Undersecretaries occupy gazetted civil service posts in India, unlike in some Western democracies, where they are political appointees.
An undersecretary will typically report to a deputy secretary, or a director to the Government of India.
The position has existed since the early 19th century, being second-in-command to the minister, although since the 1970s it has been displaced by secretaries of state.